T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
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magnesium phosphate. Nothing new is claimed for t h e work. T h e superphosphate used was home-made from ground rock. All b u t a b o u t three-quarters of one per cent of t h e phosphoric acid was water-soluble. Aqua regia was used t o dissolve the phosphoric acid. For the determination of t h e phosphoric acid various procedures were carried o u t as follows: A-The Official Method.’ B-The Official Method modified b y evaporating t h e liquid on a water b a t h , taking u p with dilute nitric acid and filtering t h r o u g h paper t o remove silica before precipitation. C-Direct weighing of t h e yellow precipitate as outlined b y Baxter.2 D-The volumetric process of Pemberton as described b y wile^.^ E-The direct precipitation of ammonium magnesium phosphate in t h e presence of ammonium citrate. F-Same as E, substituting citric acid for a m monium it rate.^ None of these methods require description. However, t h e a p p a r a t u s used for heating the yellow precipitate t o 2g0°-3000, as outlined b y Baxter, will be described. T h i s consisted of t w o 6411. iron dishes, deep form, such as are used for sand baths. T h e edges of one dish were cut back a/4 in. every half inch a n d bent i n so as t o make a cover for t h e uncut dish. A hole in t h e t o p of t h e cover held a cork a n d thermometer. Triangles inside were arranged t o hold t w o or three crucibles, each covered with a small watch glass. An asbestos jacket consisting of a side a n d t o p prevented t h e radiation of heat. T h e whole was heated with a Bunsen burner, t h e flame being protected from draft b y a n iron conical shield 8 i n . high. T h e results obtained b y t h e different methods are given in Table I, each determination made being listed. TABLE I-TOTAL PHOSPHORIC ACID IN SUPERPHOSPHATE Average DUPLICATES Per METHOD Per cent cent A-Official Method.. . 15.30 15.25 15.28 B-Official Method (modified) ......... 15.07 14.97 15.02 C-Direct weight of 14.81 14.81 yellow pp t 14.82 14.85 1 4 . 8 2 C1-Same as C but overheated. 14.53 1 4 . 5 4 1 4 . 5 4 D-V o 1 u m e t r i c method. .......... 14.80 14.86 14.83 E-Pptd. as NH4Mg14.85 1 4 . 9 4 Pod.. 14.85 14.87 1 4 . 8 8 F-Pptd. as NHaMgPod.. 16.50 16.29 16.39
.........
.......
.............
.............
Variation from B Per cent REMARKS f 0 . 2 6 No silica removed. 0.00
Silica removed
-0.20
Temp. 29O0-3OO0
-0.48
Temp. 30Oo-33O0
-0.19
KOH : HNOi
-0.14
In am. citrate
f1.37
I n citric acid
F r o m t h e comparison of t h e results given under A a n d B in Table I i t would be inferred t h a t there was 0.26 per cent of silica in the pyrophosphate when the solution of total phosphoric acid before precipitation with molybdate was n o t evaporated t o dryness. T h e results indicated under C, D a n d E, which were Bull. 107, p 2. A m . Chem. J . , 39 (1902), 298. 3 Wiley. “Principles and Practice of Agricultural Chemistry,” I1 (1908), p. 160. 6 Wiley. I b i d . . I1 (1908). p. 88. b Wiley, I b i d . . I1 (1908). p. 98. 1 1
Vol. 7, No.
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obtained b y direct weighing of t h e yellow precipitate b y t h e volumetric method a n d b y precipitation in ammonium citrate, are, on t h e average, 0.17 per cent less t h a n those listed under B. If t h e results obtained under B-silica-free-are t a k e n as s t a n d a r d , then i t is a p p a r e n t t h a t either of t h r e e more rapid methods (C, D or E) give as accurate results as t h e Official Gravimetric Method. No a t t e m p t was made t o find silica in a n y of t h e precipitates a s its presence is generally acknow1edged.l T h e results given under CI show t h e decomposition of ammonium molybdate b y temperature over 300 O a n d the resulting negative error. c 0 NC L U S I 0N T h e above work emphasizes what is already known: I-That the Official Gravimetric Method of determining total phosphoric acid gives high results when phosphoric acid is determined in superphosphate witho u t evaporation of the solution t o dryness on a s t e a m b a t h t o remove silica. 11-That several methods other t h a n the Official Gravimetric give equally good results in half t h e time. DEPARTMENT OF GENERAL AND AGRICULTURAL CHEMISTRY MASSACHUSETTS AGRICULTURAL COLLEGE, AMHERST
CLEANING SOILS FOR MlCROSCOPIC EXAMINATION By W. H. FRY AND JOHN A. CULLEN Received Oct. 22, 1914
I n m’icroscopic mineralogical work on soils i t is necessary t h a t t h e grains be t r a n s p a r e n t or a t least strongly translucent a n d t h a t the grain-surf aces be free f r o m all coatings sand adhering material. Where light is not t r a n s m i t t e d , t h e optical properties of t h e minerals cannot be determined i n soil preparations; a n d where t h e material carries a n appreciable coating of some foreign substance the refractive index determined will be t h a t of the coating instead of t h e mineral, even though t h e determination of other optical properties of t h e grain under examination may remain unaffected. M a n y soils have their constituent grains more or less stained a n d coated b y various substances. Often simple washing a n d drying serve t o render t h e m adaptable t o microscopic examination. B u t in a great number of cases t h e grains are so coated with iron oxides, hydroxides, or b o t h , t h a t other means of cleansing have t o be resorted to. T h a t cleansing agent would be most efficient which, while entirely removing the iron a n d other stains, a t t h e same t i m e h a d t h e least decomposing action on the minerals themselves. Hydrochloric a n d nitric acids act very energetically upon apatite, t h e determination of t h e presence of which is sometimes t h e primary object of t h e examination. Sulfuric acid cannot be used for t h e same reason, a n d in addition has t h e disadvantage of decomposing biotite, a common soil constituent. Several readily available organic acids were tested on various soils, different concentrations of the various acids being used in order t o ascertain t h e most efficient 1
Wiley, loc. c i f . , p. 78.
Jan., 1915
T H E J O C R N A L O F I X D I j S T R I A L A ATD E,VGI A\T E E RI S G C H E M I S T R Y
strength. It has been found t h a t , i n general, I O per cent oxalic acid best serves t h e purpose. I n about 30 minutes i t removes t h e iron stains satisfactorily. Tests upon various soil minerals showed t h a t , with t h e exception of apatite, i t did not affect t h e m appreciably; a n d in t h e case of apatite, although there is undoubtedly some effect, i t leaves t h a t mineral in a
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determinable state. Of course, in any case calcite would be removed-a fact which renders very difficult the determination of small quantities of this mineral in discolored soils. BUREAUOF SOILS
u. s. DEPARTMENT OF AGRICULTURE WASHINGTON
LABORATORY AND PLANT REPORT OF THE SELBY SMELTER COMMISSION Received December 8, 1914
T h e filing of t h e report, findings a n d recommendations of t h e Selby Smelter Commission with t h e Superior Court of Solano County settles finally a n d conclusively t h e long continued controversy between t h e residents of Benicia a n d t h e adjacent agricultural country a n d t h e Selby Smelting and Lead Company concerning t h e alleged disagreeable a n d injurious effects produced b y t h e smoke from t h e Selby Smelter. T h e smelter operated b y t h e Selby Smelting a n d Lead Company is situated near Vallejo Junction in Contra Costa County, California, a t t h e western end of t h e Carquinez Straits. The City of Benicia is situated in Solano County at t h e eastern end of t h e Straits, about five miles from t h e smelter. During nine months of t h e year t h e prevalent trade winds blow t h e smoke from t h e Selby Smelter over a n d into t h e City of Benicia a n d t h e agricultural area lying between Benicia a n d Vallejo. On March 14, 1905, action was brought by t h e District Attorney of Solano County, California, in t h e Superior Court of Solano County, praying for a n injunction which would restrain a n d enjoin t h e i s e l b y Smelting a n d Lead Company from permitting injurious smoke a n d gas from t h e Selby Smelter t o blow over a n d upon t h e City of Benicia a n d t h e tributary country. T h e case was brought t o trial on August 7 , 1906, a n d judgment of t h e Court in favor of t h e Plaintiff was rendered on July 16, 1908. T h e decree of t h e Court was t o t h e effect t h a t during eight months of each year between t h e 15th of March a n d t h e 15th of November, t h e Selby Company was enjoined from discharging noxious gases a n d fumes into t h e open air in such a manner t h a t t h e same would be carried into a n d upon t h e City of Benicia a n d t h e tributary country in Solano County i n such quantities as t o be offensive t o t h e senses a n d t o interfere with t h e comfortable enjoyment of life a n d property. After motion for a new trial was made b y t h e Defendant a n d denied b y t h e Court, a n appeal was thereupon taken t o t h e Supreme Court of t h e State. On June 12, 1912, t h e judgment of t h e trial court mas affirmed b y t h e Supreme Court. During t h e period covered b y this litigation t h e Selby Company h a d been making efforts toward t h e elimination of some of t h e objectionable constituents of t h e smoke, these efforts having resulted in t h e removal of t h e major portion of lead, arsenic a n d sulfur trioxide from t h e smelter smoke,
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I n t h e spring of 1913, although t h e Selby Company maintained t h a t they had abated t h e nuisance, complaints mere made by t h e residents of t h e area t h a t a nuisance still existed, a n d t h a t t h e decree of t h e Court was, therefore, being violated b y t h e Smelting Company. Various considerations, among them the prospective heavy expense which would accrue t o both parties t o the litigation as a result of a trial of the Smelter Company for contempt of Court, led t o conferences of t h e attorneys representing both sides, which resulted in a n agreement t o submit t h e question of fact a s t o t h e violation of t h e decree of injunction t o a board of technically trained men, deemed b y both sides t o be qualified t o act in such a capacity, and equal financial responsibility of t h e parties in t h e expense of t h e Commission’s activities. T h e result of t h e agreement was t h e filing of a stipulation in t h e record of t h e cause providing for such a board. 0 R GA NI Z AT1 0 N 0 F C 0 M 31 IS S I 0 N
On M a y 2 2 , 1913, this board was organized as t h e Selby Smelter Commission, with the . following personnel : J. A . HOLMES, Director U. S. Bureau of Mines. (at the time of appointment Chief of the E. C. FRANKLIN Chemical Division of the Hygienic Laboratory of the L.S. Public Health Service), Professor of Organic Chemistry, Leland Stanford, Jr., University. RALPHA . GOULD, Chemical Engineer, San Francisco, Secretary of the Commission. The function of t h e Selby Smelter Commission was t o determine t h e facts a n d report its findings on t h e following: 1-1s the Selby Smelter operating in such a manner as to violate the decree of the Court dated July 16, 1908? 2-If the Defendant Company is violating the decree, what is the extent of the violation? 3-If the Defendant Company is violating the decree, what steps must be taken by the Defendant to avoid a violation of the decree? For the determination of facts, the Commission a n d its staff have carried on very careful and complete investigations of all matters which in t h e opinion of t h e Commission could have a n y bearing on t h e questions at issue a n d t o be answered. These investigations were made b y the following staff of trained scientific a n d technical men, no one of whom, otherwise t h a n in arriving a t t h e t r u t h , was directly or indirectly interested in t h e findings of t h e Commission: A E. WELLS,Metallurgist and Chief Chemist, in charge of Smelter Investigations and Field Work. C. B. DUTTON,Special Legal Agent, U. S. Bureau of Mines.
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